1. Field of the Invention
This invention relates to a reversible window structure capable of reversing a sash housed in a window frame. More particularly, the invention is concerned with a reversible window structure which can completely prevent the protruding of the sash from the window frame toward the indoor side during the reversing of the sash and can be reversed through a considerably light operating force by moving a gravity center of the sash in a substantially horizontal state toward the outdoor direction.
2. Description of Prior Art
As a window structure capable of turning a sash housed in a window frame inside out at indoor and outdoor sides, there have hitherto been known vertically rotatable windows and horizontally rotatable windows. In such rotatable windows, however, when the sash is rotated around a vertical or horizontal axis to turn its indoor and outdoor surfaces inside out, both up and down sides or both sides of the sash protrude toward outdoor and indoor sides, respectively, in the course of the turning. Therefore, if a curtain, blind or the like is arranged at the indoor side, it not only obstructs the turning of the sash but also possibly inflicts an injury on persons existent in the room.
For this reason, there is proposed a vertically reversible window adopting the conventional vertically rotatable system but modifying the structure thereof, in which upper and lower portions at one end side of the sash in right and left direction are engaged with upper and lower window frames, respectively, and the thus engaged parts are rotatably moved along the upper and lower window frames in the transverse direction so that substantially the whole of the sash protrudes from the window frame toward the outdoor side but does not protrude toward the indoor side during the reversing of the sash.
In such a vertical reversible window, however, only the one end side of the sash in right and left direction is supported at the engaged part on the upper and lower window frames during the reversing of the sash or at a so-called cantilever state, so that there is particularly a fear of deforming the framing of the sash in case of windows having a longer opening width. If such a deformation is caused, it is difficult to open and shut the sash due to the close contacting of the sash with the window frame, resulting in the injuring of them. Further, the sound insulating performance and water-proof performance are insufficient. Therefore, the conventional vertically reversible window is difficult to be applied to windows with a large opening width.
On the other hand, the inventors have previously developed a reversible window structure utilizing the horizontal rotation system in which the sash can be reversed without protruding toward the indoor side by freely moving one end in the up and down direction of the sash member along the vertical window frames in the up and down direction and pivotably supporting the vertical sash frame member at a position substantially corresponding to a gravity center of the sash. Further, the inventors have made various studies with respect to the concrete improvement of such a reversible window structure. For instance, when the vertical sash frame member is pivotably supported at a position substantially equal to the gravity center of the sash member, the upper end of the vertical sash frame member is pivotably supported by a lower end of a supported arm pivoted to an upper portion of the vertical window frame at such a position that the vertical sash frame member is substantially at the same level as the gravity center of the sash. In this case, the gravity center of the sash changes in up and down direction in accordance with the pivot radius of the arm during the reversing of the sash, so that a large operating force is required and at the same time the reverse operation is apt to become unstable. As a result of the continuation of further studies, the invention has been accomplished.